Umbraco-CMS/src/Umbraco.Core/NameValueCollectionExtensions.cs

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Text;

namespace Umbraco.Core
{
	internal static class NameValueCollectionExtensions
	{

		public static bool ContainsKey(this NameValueCollection collection, string key)
		{
			return collection.Keys.Cast<object>().Any(k => (string) k == key);
		}

        public static T GetValue<T>(this NameValueCollection collection, string key, T defaultIfNotFound)
        {
            if (collection.ContainsKey(key) == false)
            {
                return defaultIfNotFound;
            }

            var val = collection[key];
            if (val == null)
            {
                return defaultIfNotFound;
            }

            var result = val.TryConvertTo<T>();
            
            return result.Success ? result.Result : defaultIfNotFound;
        }
	}
}